One of the curses of surviving any form of abuse is that tickling in the back of the mind asking,
"Did this really happen?"
or
"Well, it wasn't THAT bad."
Defining abuse for ourselves, as survivors, is a process... not a one moment event.
Validation can come from many places, but seeing concrete definitions of what is considered child abuse by the law is a good place to start.
Here is an excellent resource to help you navigate through the laws regarding child sexual abuse:
Sex Abuse and Exploitation Laws
Loretta Kelly, MSW